Earth’s earliest chapter is mostly gone. Rocks from the planet’s first few billion years have been eroded, buried, recycled, or dragged back into the mantle. This has left only scattered traces of the world in which life first appeared. Therefore, every surviving clue is unusually valuable, especially when scientists are trying to answer a basic question. How often did giant impacts strike the young inner solar system while life was beginning on Earth? A lunar meteorite recovered in northwest Africa is now offering one of those clues. In a study published in Geology, researchers report that the rock records a major impact on the Moon about 3.486 billion years ago. The age closely matches evidence of ancient impacts preserved on Earth. It also matches impact ages tied to 4 Vesta, the fourth-largest object in the asteroid belt. That rare overlap, the team says, helps connect the histories of three different bodies at a time when the inner solar system was still getting hammered. This happened long after the most chaotic phase of planet formation had …